The nature of these projects are long term; therefore, the progress made each year is incremental. The project to establish a gene which when homozygous results in obesity in rats in two different inbred strains has yielded a model which may have potential for the study of adult onset diabetes mellitus. The evidence suggests that the resulting diabetes is the consequence of the underlying resistance to insulin rather than obesity per se since the disease was apparent only in the insulin resistant strain but not in the insulin senstitive strain. The preliminary results of a second study concerned with the development of immunodeficient mice by establishing mutations which affect the functioning of the immune system suggest that these mice may have promise for cancer research and parasitology since their immune systems appear to be quite similar to animals which have been severely immunocompromised by the use of chemicals. Additional studies are currently underway for confirmation.